Deputy Marshal Samuel Gerard: Well, what does that mean Biggs, 'hinky'?Hinky - A state of being vaguely suspicious.
Marshal Biggs: I don't know. Strange.
Marshal Henry: Weird.
Gerard: Well, why don't you say strange or weird? I mean hinky, that has no meaning.
Biggs: Well, we say hinky.
Gerard: I don't want you guys using words around me that have no meaning. I'm taking the stairs and walking.
Biggs: [sotto voice] How about 'bullshit?' How about 'bullshit', Sam?
~ The Fugitive (1993)
I love words like this that drive etymologists crazy. Some say it comes from an Old Scottish word, hink, meaning hesitation. Others trace it to the word hank, meaning a coil of rope. Still others trace the word to hincty, black slang from the Roaring Twenties (via hanky) meaning snobbish. Then there are those who swear it comes from the German word hinken, meaning to limp.
Then again, it could just come from a child's rhyming game, hinky-pinky.